Everyone Knows In The Spirit World
Most humans do not yet know or accept the reality that Jesus of Nazareth is the Son of God, the Messiah. People of other religions obviously do not accept Christianity. Most of the Christ's fellow Jews do not accept Him as the long-awaited Messiah. Even most of those who profess to be Christian do not truly know Christ (see I Did It My Way and Do You Know Him?). But in the spirit world, everyone, good or evil, knows Who the Son of God is.
"Let all God's angels worship Him"
Righteous angels all know who and what Christ is.
"And again, when He brings the first-born into the world, He says, "Let all God's angels worship Him. Of the angels He says, "Who makes His angels winds, and His servants flames of fire." (Hebrews 1:6-7 RSV)
"And I tell you, every one who acknowledges Me before men, the Son of man also will acknowledge before the angels of God; but he who denies Me before men will be denied before the angels of God." (Luke 12:8-9 RSV)
Satan knows who and what Christ is (note that Satan actually quoted Holy Scripture to Christ!).
"And the tempter came and said to Him, "If you are the Son of God, command these stones to become loaves of bread."
But He answered, "It is written, 'Man shall not live by bread alone, but by every word that proceeds from the mouth of God.'"
Then the devil took Him to the holy city, and set Him on the pinnacle of the Temple, and said to Him, "If you are the Son of God, throw yourself down; for it is written, 'He will give His angels charge of you,' and 'On their hands they will bear you up, lest you strike your foot against a stone.'"
Jesus said to him, "Again it is written, 'You shall not tempt the Lord your God.'"
Again, the devil took Him to a very high mountain, and showed Him all the kingdoms of the world and the glory of them; and he said to Him, "All these I will give you, if you will fall down and worship me."
Then Jesus said to him, "Begone, Satan! For it is written, 'You shall worship the Lord your God and Him only shall you serve.'" (Matthew 4:3-10 RSV)
Demons all know who and what Christ is.
"And He healed many who were sick with various diseases, and cast out many demons; and He would not permit the demons to speak, because they knew Him." (Mark 1:34 RSV)
"Ah! What have you to do with us, Jesus of Nazareth? Have you come to destroy us? I know who you are, the Holy One of God." But Jesus rebuked him, saying, "Be silent, and come out of him!" And when the demon had thrown him down in the midst, he came out of him, having done him no harm. And they were all amazed and said to one another, "What is this word? For with authority and power he commands the unclean spirits, and they come out." (Luke 4:34-36 RSV)
"And when He came to the other side, to the country of the Gadarenes, two demoniacs met Him, coming out of the tombs, so fierce that no one could pass that way. And behold, they cried out, "What have you to do with us, O Son of God? Have you come here to torment us before the time?" (Matthew 8:28-29 RSV)
Fact Finder: Do demons have the same sort of "faith" that some Christian-professing people do?
See James 2:17-19 and the study entitled James 2:17